There is a growing shadow campaign to defend Joe Biden from House Republicans

As Republicans prepare to use their new House majority to probe the Biden administration and the business dealings of the president's son, Hunter, Democrats are assembling a constellation of groups to respond.

President Joe Biden hasn’t said if he’s running for re-election, but the groups are designed to defend him and discredit the opposition — including launching intense opposition research efforts into Republicans leading the charge in Congress — ahead of a likely rematch with former President Donald Trump in 2024.

Three new "war rooms" have sprung up in the past two...